溶胶-凝胶法制备B掺杂TiO_2纳米粉体及其光催化性能研究

Preparation and Photocatalytic Properties of B-doped TiO_2 Nano-powder by Sol-gel Method

本研究采用溶胶-凝胶法制备了B掺杂TiO_2纳米粉体。采用X射线衍射(XRD)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、紫外可见漫反射光谱(UV-Vis)等测试手段对其进行了表征,以亚甲基蓝为模拟污染物,评价了不同热处理条件下的粉体在可见光下的光催化活性。结果表明:B掺杂对TiO_2表面形貌没有明显影响,但抑制了TiO_2晶粒的长大和TiO_2由锐钛矿型向金红石型的转变;部分B以B_2O_3的形式存在,部分B掺入到TiO_2晶格间隙形成B-O-Ti键;B掺杂未改变TiO_2的吸收边带,且使得TiO_2对可见光的吸收有所减弱;B掺杂能有效促进TiO_2表面活性基团Ti-OH的生成,该基团能够有效捕获空穴,从而提高光催化活性;B掺杂TiO_2粉体在650℃煅烧的催化活性最高,对亚甲基蓝的2 h降解率比未掺杂TiO_2提高16.51%。

In this work, B-doped TiO2 nano-powders were prepared by a sol-gel method. The powders were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, X-ray photoelectron spectroscopy （XPS） and UV-Vis spectrophotometer techniques. The photocatalytic activities of the powders prepared under different heat treatment conditions were evaluated according to their photodegradation behavior to methylene blue in visible light. The results indicated that B doping had no obvious effect on the surface morphology of TiO2, but inhibited the growth of TiO2 grains and the transformation of TiOz from anatase to rutile. Some B in the form of B2 O3, some B incorporated into the TiO2 lattice gap to form B-O-Ti bond. B doping had no change on the absorption edge of TiO2, and also weakened the absorption of TiO2 to visible light. B doping could effectively promote the formation of TiO2 surface active group Ti-OH, which could availably capture the photon-generated hole, thus improving the photocatalytic activity of TiO2. The B-doped Ti02, calcined at 650 ℃, had the highest visible photocatalytic activity, and was 16.51% higher than that of the undoped TiO2 in the 2 h degradation rate of methylene blue.